BIO373H5 Lecture Notes - Lecture 17: Industrial Microbiology, Glycoside Hydrolase, Nitrogen Fixation
Document Summary
Neutralism: lack of interactions; low pop densities and low growth rates. Commensalism: one way positive exchange; one organism"s benefits from another"s scraps. Symbiosis: two way positive exchange that allows a new biological trait to be expressed. Competition: organisms compete for nutrient limiting resources. Amensalism: one way negative exchange; one organisms is antagonistic to another. Parasitism: little debilitates big over prolonged period; parasite may require host" relationship can be balanced or destructive. Ecto-mycorrhizae partners are trees and shrubs and soil fungi; resource exchange is fungi inhabiting root cortical cells and obtain carbon from plant but root is enveloped in fungal network (root tissue is surrounded not penetrated) N2 fixing cyanobacteria ferns and bacteria; small floating fern provides cavities within its leaves that serve as habitat for cyanobacteria and the bacterium fixes nitrogen in intracellular association. Protozoa intracellular symbiont (protozoa) and many types of bacteria and amoeba; by colonizing interior of protozoa, bacteria generally receive food and shelter.
